 function bore(b,r,f,      id,c,v,f1,f2,c,tmp,id) {
   for(v in f[1]) {
       n1   = f[1][v]
       n2   = f["*"][v] - n1
       best = n1 / b
       rest = n2 / r
       if (best > rest) {
         id++
         tmp[id]["c"] = c
         tmp[id]["v"] = v
         tmp[id]["val"] = best^2 / (best + rest) 
   }}
   return asort(tmp,ranks,"valdesc")
 }
